[libxslt] Also rebuild devhelp files when rebuilding documentation

[Nick Wellnhofer <nwellnhof src gnome org>]

commit a074454aa6da97d4812d53a2e2566dc0b79c7119
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Wed Aug 17 11:14:30 2022 +0200

    Also rebuild devhelp files when rebuilding documentation

 doc/Makefile.am | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 2f637b84..b7f7510e 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -49,5 +49,7 @@ rebuild:
          --nonet $(WIN32_DIR)/defgen.xsl libxslt-api.xml
        cd $(srcdir) && $(XSLTPROC) -o $(WIN32_DIR)/libexslt.def.src \
          --nonet $(WIN32_DIR)/defgen.xsl EXSLT/libexslt-api.xml
+       cd devhelp && $(MAKE) rebuild
+       cd EXSLT/devhelp && $(MAKE) rebuild
 
 .PHONY: rebuild